/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved. 
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 * 
 * Author: Adam Dunkels <adam@sics.se>
 *
 */

#ifndef __LWIP_PBUF_H__
#define __LWIP_PBUF_H__

#include "lwip/opt.h"
#include "lwip/err.h"

#ifdef __cplusplus
extern "C"
{
#endif

#define PBUF_TRANSPORT_HLEN 20
#define PBUF_IP_HLEN        20

  typedef enum
  {
    PBUF_TRANSPORT,
    PBUF_IP,
    PBUF_LINK,
    PBUF_RAW
  } pbuf_layer;

  typedef enum
  {
    PBUF_RAM,			/* pbuf data is stored in RAM */
    PBUF_ROM,			/* pbuf data is stored in ROM */
    PBUF_REF,			/* pbuf comes from the pbuf pool */
    PBUF_POOL			/* pbuf payload refers to RAM */
  } pbuf_type;


/** indicates this packet's data should be immediately passed to the application */
#define PBUF_FLAG_PUSH 0x01U

  struct pbuf
  {
  /** next pbuf in singly linked pbuf chain */
    struct pbuf *next;

  /** pointer to the actual data in the buffer */
    void *payload;

  /**
   * total length of this buffer and all next buffers in chain
   * belonging to the same packet.
   *
   * For non-queue packet chains this is the invariant:
   * p->tot_len == p->len + (p->next? p->next->tot_len: 0)
   */
    u16_t tot_len;

  /** length of this buffer */
    u16_t len;

  /** pbuf_type as u8_t instead of enum to save space */
      u8_t /*pbuf_type */ type;

  /** misc flags */
    u8_t flags;

  /**
   * the reference count always equals the number of pointers
   * that refer to this pbuf. This can be pointers from an application,
   * the stack itself, or pbuf->next pointers from a chain.
   */
    u16_t ref;

  };

/* Initializes the pbuf module. This call is empty for now, but may not be in future. */
#define pbuf_init()

  struct pbuf *pbuf_alloc (pbuf_layer l, u16_t size, pbuf_type type);
  void pbuf_realloc (struct pbuf *p, u16_t size);
  u8_t pbuf_header (struct pbuf *p, s16_t header_size);
  void pbuf_ref (struct pbuf *p);
  void pbuf_ref_chain (struct pbuf *p);
  u8_t pbuf_free (struct pbuf *p);
  u8_t pbuf_clen (struct pbuf *p);
  void pbuf_cat (struct pbuf *head, struct pbuf *tail);
  void pbuf_chain (struct pbuf *head, struct pbuf *tail);
  struct pbuf *pbuf_dechain (struct pbuf *p);
  err_t pbuf_copy (struct pbuf *p_to, struct pbuf *p_from);
  u16_t pbuf_copy_partial (struct pbuf *p, void *dataptr, u16_t len,
			   u16_t offset);

#ifdef __cplusplus
}
#endif

#endif				/* __LWIP_PBUF_H__ */
